Response of Land Surface Processes to Global Warming and Its Possible Mechanism Based on CMIP3 Multi-model Ensembles
陆面过程对全球变暖的响应及可能机制——基于CMIP3的多模式集合分析

Based on the model results of the 20th century (The Twentieth-Century Climate in Coupled Models, 20C3M) and 21st century (SRES A1B scenario) simulations given by 12 climate models under Phase 3 of the Coupled Model Intercomparison Project (CMIP3), the thermal and hydrological responses of land surface processes to global warming together with their possible mechanisms are investigated by comparing the land surface energy and hydrological variables in the 21st century with those in the 20th century.Compared with those in the 20th century, the global averages of land skin temperature, surface net radiation and latent heat flux in the 21st century increase significantly, but the sensible heat flux decreases on the whole. In the aspect of the hydrological response, evident increasing trends are found in precipitation, surface evaporation and runoff, but decreasing trends in the soil water content. According to the linkages between the land surface variables and the atmospheric forcing variables under global warming, it is found that the thermal responses of the land surface to global warming are mainly induced by the changes of the air temperature and downward longwave radiation, however the hydrological variability of the land surface is dominated by the variation of the air temperature. Further investigation suggests that there are significant regional differences in both the thermal and hydrological responses of the land surface to global warming. The change of land skin temperature and sensible heat flux is remarkable, especially over mid-high latitudes of the Northern Hemisphere. And the response of net radiation and latent heat flux to global warming is significant in central Asia and Africa. The contribution of temperature and downward longwave radiation becomes more important in the 21st century compared with the 20th century. The land surface hydrological cycle exhibits significant responses to global warming in Asia and North America. And the contribution of temperature is more important in the 21st century especially in middle latitudes of the Northern Hemisphere compared with the 20th century.